Antipsychotics, Mood & Anxiolytics

Correct: B

Tempting to call this NMS: fever plus a psychiatric patient on antipsychotics is the classic NMS setup. The trap is that NMS requires rigidity, markedly elevated CK, and autonomic instability, none of which are present. Mouth ulcers and sore throat point directly to agranulocytosis (neutropenia eliminates mucosal immune defenses). Think of clozapine's mandatory CBC monitoring like a smoke detector with a mandatory weekly test: you don't skip the test just because the house seems fine. Clozapine causes agranulocytosis in approximately 1-2% of patients. The mandatory monitoring protocol requires weekly CBC (specifically ANC) for the first 6 months, then biweekly, then monthly. Fever + sore throat + mouth ulcers in a patient on clozapine = treat as agranulocytosis until proven otherwise. If ANC drops below 1500/mm3, clozapine must be stopped and the patient is permanently barred from re-challenge.

Why the others are wrong: This is not an NMS presentation (no rigidity, no markedly elevated CK, no autonomic instability). Hepatotoxicity would present with jaundice/elevated transaminases. Lithium is not clozapine.

Break it down: clozapine = mandatory weekly CBC for 6 months, then biweekly, then monthly; fever + sore throat + mouth ulcers = stop clozapine and check ANC immediately; ANC below 1500 = permanent ban from clozapine; NMS requires rigidity and elevated CK.

Correct: B

Tempting to avoid all benzodiazepines in liver disease and pick the one you're least familiar with, or to just pick the shortest-acting agent. The trap is that half-life is not the key variable in liver disease: CYP pathway dependence is. Think of the liver's detox capacity in cirrhosis as a factory with two assembly lines. The CYP oxidation line is completely shut down (diazepam, chlordiazepoxide, midazolam all pile up). The glucuronidation line keeps running with minimal staffing (lorazepam, oxazepam, temazepam are processed safely). The LOT drugs (Lorazepam, Oxazepam, Temazepam) undergo glucuronidation instead of CYP-dependent hepatic oxidation. In liver disease, CYP enzymes are impaired and drugs metabolized by them will accumulate to toxic levels. Glucuronidation is relatively preserved even in significant liver disease. Lorazepam and oxazepam also lack active metabolites, preventing buildup of sedating byproducts.

Why the others are wrong: Diazepam and chlordiazepoxide have long half-lives and active metabolites that depend on CYP450 and will accumulate dangerously in cirrhosis. Midazolam is hepatically oxidized despite its short half-life.

Break it down: liver disease + benzodiazepine = LOT drugs only (Lorazepam, Oxazepam, Temazepam); LOT = glucuronidation (preserved in cirrhosis), no active metabolites; diazepam, chlordiazepoxide, midazolam = CYP-dependent = accumulate in liver disease.

Correct: B

Tempting to pick C (hold lithium and recheck levels): if lithium is toxic, stopping it makes sense. The trap is that ibuprofen is the trigger driving lithium retention, and simply holding lithium temporarily doesn't fix the mechanism. Think of lithium and sodium as two siblings fighting for the same proximal tubule seat on the bus. NSAIDs reduce renal blood flow and GFR, so the bus takes fewer riders total, and the kidney grabs every sodium (and lithium) it can find. Stop the ibuprofen to free up the seats before adjusting lithium. Lithium is not protein-bound and is not metabolized by the liver. It is excreted renally, competing with sodium at the proximal tubule. NSAIDs inhibit prostaglandin synthesis, which reduces renal blood flow and GFR. The kidney compensates by increasing sodium (and lithium) reabsorption at the proximal tubule. The result: lithium accumulates to toxic levels.

The same mechanism applies to: thiazide diuretics (volume depletion triggers Na+/Li+ reabsorption), ACE inhibitors (reduce GFR directly), and dehydration from any cause. These are the four major lithium toxicity triggers. Break it down: NSAIDs raise lithium levels by reducing GFR and increasing proximal tubule Na+/Li+ reabsorption; same mechanism applies to thiazides, ACE inhibitors, and dehydration; lithium toxicity = coarse tremor, confusion, ataxia, seizures; treat by stopping the offending drug and hydrating.

Correct: C

Tempting to call this acute dystonia or drug-induced parkinsonism since antipsychotics cause both. The trap is the timeline: "tardive" means late-appearing (months to years), not hours to weeks. Think of antipsychotic side effect timing as a calendar: acute dystonia appears in hours to days (day 1-4), parkinsonism appears in weeks (1-4 weeks), tardive dyskinesia appears in months to years (the late consequence of D2 receptor supersensitivity). The orofacial choreiform movements are the signature. This is tardive dyskinesia (TD). The word "tardive" means late-appearing. It develops after months to years of antipsychotic use, caused by D2 receptor supersensitivity from chronic blockade. Orofacial movements (lip smacking, tongue protrusion, chewing) are classic. The movements are often noticed by others before the patient (reduced insight).

Treatment: First step is reducing the dose or switching to a lower-EPS atypical (clozapine or quetiapine). Valbenazine and deutetrabenazine (VMAT2 inhibitors) are FDA-approved specifically for TD.

Critical point: Benztropine is used for dystonia and parkinsonism but is NOT effective for TD and may actually worsen it. The anticholinergic shift worsens the dopaminergic supersensitivity underlying TD. Break it down: tardive dyskinesia = months to years of D2 block, receptor supersensitivity, orofacial choreiform movements; acute dystonia = hours to days (anticholinergics fix this); DIP = weeks (dose reduction or anticholinergics); TD treatment = dose reduction, switch to clozapine/quetiapine, or valbenazine/deutetrabenazine (VMAT2 inhibitors).